The present invention relates generally to swim fins, and more particularly, is directed to a swim fin that increases the surface area for propulsion.
It is well known to use swim fins or flippers on a person's feet when swimming for providing added propulsion to the swimmer. Such swim fins include a blade or flipper on which is provided an arcuate encasing wall extending upwardly from the blade at one end thereof so as to define a foot receiving recess between the blade and arcuate encasing wall. The recess has a closed toe portion at one end and an opening at the opposite end through which a person can insert his or her foot into the foot receiving recess. A strap is provided at the open end to maintain the person's foot in the foot receiving recess. The swim fin is preferably made of a material such as a molded rubber having a suitable hardness to impart durability, while at the same time, being flexible and resilient, thereby allowing the swim fin to flex a little during a swimming stroke.
However, the problem with conventional swim fins is that the surface area for propulsion is generally limited to that of the flat blade portion.
It is known to increase the surface area of a swim fin, for example, by providing multiple, parallel, spaced apart layers, as disclosed in U.S. Pat. No. 5,330,377. However, such a construction greatly increases the size of the swim fin, making it unwieldy to use, and making it nearly impossible to walk on dry land.
It is also known to provide pivoting hydrofoil blades in a swim fin, as disclosed in U.S. Pat. No. 5,536,190. However, these do not increase the surface area for propulsion.